Roller furnace construction and method of maintenance operation



Feb. 3, 1959 E. w. LINDQUIST ROLLER FURNACE CONSTRUCTION AND METHOD OFMAINTENANCE OPERATION Filed Jan. 8, 1954 4 Sheets-Sheet l a D o a o ol(||| E. W. LINDQUIST ROLLER FURNACE CONSTRUCTION AND Filed Jan. 8, 19544 Sheets-Sheet 2 :Fig. 3.

INVENTOR ELMER W. LINDQUIST Feb. 3, 1959 Efw. OLINDQUIIST ROLLER FURNACECONSTRUCTION AND METHOD OF MAINTENANCE OPERATION Filed Jan. 8, 1954 4Sheets-Sheet 3 INVENTOR} ELMER W LINDQUIST Feb. 3, 1959 E. w. {.INDQUIST2,872,174

ROLLER FURNACE CONSTRUCTION AND METHOD OF MAINTENANCE OPERATION FiledJan. 8, 1954 4 Sheets-Sheet 4 INVENTOR ELMER W. LINDQUIST United SttesPatent f ROLLER FURNACE CONSTRUCTION AND METHOD OF MAINTENAN OPERATIONElmer W. Lindquist, Montgomery Township, Montgomery County, Pa.,assignor to Drever Company, Bethayres, Pa., a corporation ofPennsylvania This invention relates to a new furnace constructionemploying a roller hearth and to a method of maintaining such furnace.More particularly, this invention pertains to a new furnace providingnovel roller installation and mounting means and to a new method ofinstalling, removing, and changing rolls in such a furnace.

Roller hearth furnaces are Widely known and used in the metallurgicaland other industries for a host of purposes. In such furnaces, a hearthor conveying bedis provided by a plurality of transversely extendingparallel rollers, the axes of which are usually horizontal or at leastin a common plane. In high temperature furnace service, such rollers areusually driven and the driving means as well as the bearing means forthe rollers are frequently located outside the side walls of suchfurnaces, which side walls extend between the floor and roof thereof. Inmany operations, doors are provided at the ends of the furnace above thehearth or bed so that the furnace can be substantially totally enclosedduring the periods between entry and discharge of the workpieces goingthrough the furnace. With the furnace hearth or bed above floor level,the installation of rollers and any occurrence necessitating the removalof a roller or the replacement of a roller have not been readilyconductible. In the case particularly of larger furnaces, it hasgenerally been considered necessary when any suchjoccur- 2,872,174Patented Feb. 3, 3959 Figure 6 is a view looking at the outer end of anew wall block as shown in Figure 5;

Figure 7 is a perspective view looking toward an inner end of a lower.section of a port block;

Figure 8 is a perspective view looking toward an outer side of the lowersection of the port block shown in Figure 7; I

Figure 9 is a perspective view looking at an inner end of the uppersection of a port block; t

Figure 10 is a perspective view in section, showing a new port block anda new wall block forming an embrasure closure Wall member in thatpractice of this invention illustrated in the foregoing figures;

Figure ll is a view of a new wall block similar to that shown in Figure5 with the addition of a tunnel recess to enable it to be used as aburner block for underhearth rence took place, to cool the furnacedownbefore enheight of the roller, or by disengaging the roller to beremoved from the furnace structure and taking it'out above its normaloperative position. Even in cases of smaller furnaces, when a rollerchange might be attempted without lengthy cooling down, therewas'nevertheless a material downtime with its attendant loss ofproduction in addition to relatively difficult acts involved in removingthe rollers while in a position at or above the hearth level.

In the new construction and process of this invention, the foregoingdifficulties have been overcome. Other objects and advantages will beapparent from the following description and from the accompanyingdrawings, which are illustrative only, in which Figure l is a side viewof a portion of a length of a new furnace embodying my invention and inwhich one-of the roller embrasures has been uncovered;

Figure 2 is a longitudinal view of the new structure shown in Figure 1taken along line II--II of Figure 1;

Figure 3 is a longitudinal view taken along line IIIIII of Figure 1;

Figure 4 is a view similar to the view shown in Figure 3, illustrating aroller in the process of being removed in accordance with my newmaintenance operation;

Figure 5 is a perspective view, of a new wall block which may beutilized in one practice of my invention;

floor 14 is preferably a refractory aggregate.

Figure 12 is a view in side elevation from the other side of the furnaceshown in Figure l; and

Figure 13 is a perspective View of a skid platform suitable for use inthe illustrated practice of this inventron.

Referring to the drawings, a new furnace 10 is provided whichconstitutes a practice of my invention. In that furnace, a shell isprovided comprising a bottom steel plate 11 and side steel plates 12.These-plates are secured to vertical buckstays 13 in spaced arrangementalong the two sides of furnace 10. Plate 11 which may also betransversely supported on the underside thereof may be filled with arefractory concrete mixture to provide a floor 14- inside the furnace.The level 1100,1114 may be the same as the level of outside floor15 in aplant in which furnace It? is constructed. Floor 15 may be consideredthe grade or ground level of furnace 10. The binding structure offurnace 10 may include transverse I-beams 16 secured to the upper'partsof buckstays 13, longitudinal primary channels 17 and longitudinalsecondary channels 18 to tie the structure together at the top.Stifliening channels 19 may also be used between buckstays to assist inrigidifying the furnace steel work. A longitudinal channel 24 may extendbetween buckstays 13 at grade level, the channel 20 being affixed toshell 12 and forming with I-beam jackstay 21 which is secured theretoand to shell 12, an inverted T surrounding two sides of the twoembrasures 22 in each of the bays 23 in furnace ltlbetween adjoiningbuckstays 13. Various other buckstay and binding structures may beemployed with a practice of this invention incorporated therewith.Furnace 10 may be lined with refractory. In the illustrated furnaceembodiment, which may serve as a roller hearth annealing furnace forsteel sheets and plates, In addi tion, a refractory roof 24 may besuspended from the top steel binding structure as illustrated, or anarched refractory structure might be employed utilizing keystone andskew brick arrangements as will be understood by those in the furnaceart. Side walls 25 in addition to constituting sheet 12 on the outersides thereof respectively may comprise pillars 26 of firebrick betweenembrasures 22, the tops of pillars 26 being provided with alternatelyfacing skew bricks 27 for brick arches 28 spanning the top of theembrasures 22. Firebrick courses 29 rise above the skew and arch bricks27 and 28 as shown in Figure 2 to meet the underside 30 of roof 24- andcomplete the refractory enclosure on the inside of the furnace shell.The brick courses 29 may be inter rupted by refractory framed windows 31constituting peepholes at spaced locations along the furnace, by

36 the axes 37 of which lie in a horizontal plane. As"

shown, the rollers 36 are provided with. refractory bodies but suchrollers may be made of other materials including metal and all-metalconstructions. The center lines 37 of rollers 36 are spaced to conformto the spacing of the embrasures 22 and bays 23 there being two rollers36 in each bay in the illustrated embodiment. Ends 38 of rollers 36 areof reduced diameter and extend from the insideof furnace to the outsidethereof through ports 39. Assuming work proceeds in the direction ofarrow 40 through furnace 10, right-hand end 38 of each roller 37 may beprovided with an adjustment mechanism 41 to keep the refractory body ofroller 36 under compression. The adjustment mechanism 41 may includetemperedsprings for such compression purpose. Each roller 36 issupported by its ends 38 outside the side walls 25 and shell 12 offurnace 10 to avoid interference, at thehigh temperatures usuallyprevailing in the furnace 10, with the functioning of the bearingssupporting the rollers 36. Pillow .blocks 42 having bases 43 may beemployed for such support. However, the bases 43 of bearings 42 may besecurely bolted to a horizontal flange 44 of an angle. bracket 45.Brackets 45'may have a length to precisely span the distance between abuckstay 13 and the outer flange of jackstay 21 adjacent the topthereof, the brackets 45 being bolted to the respective stays. In thisway, rollers 36 may be suspendibly mounted in the upper part ofembrasures 22 from the structural metal members, usually steel, of thefurnace 10. Hence, any roller 36 may readily be released from itssupport by unbolting the pillow blocks 42 from the brackets 45, or asreadily installed by connecting the bearings 42 to such brackets. Itwill also be noted that in the embodiment shown, the inner flange ofjackstays 21 is bolted to the lower part of the upper portion of plate12, the plates 12 on the sides being cut out in each bay between thesides of embrasures 22 nearer the adjacent buckstays 13 and between thetops and bottom of such embrasures. As shown in'Figure 1, such cuttingpreferably conforms at the top of the embrasures to the arch shape ofthe brick arches 28. I

A roller drive chain 46 may be operative on the left side of theillustrated furnace 10 in an endless chain fashion, as will beunderstood by those skilled in the furnace roller driving art. Thus,chain 46 may engage a sprocket 47 fastened to the nearer end 38 of eachroller 36 in a. horizontal upper reach of such chain 46. Disengagementof the chain may be guarded against by a hold-down angle 48 fastened toa fabricated boss 49 secured as by welding to each of the brackets 45 onthe left-hand side of furnace 10. At the ends of the furnace 10, chain46 may have vertical reaches and lower guide sprockets 50 for the lowerreturn reach 51. Guide sprockets 50 may be rotatably attached to thebottom of the nearest inverted T-member 21. A driving pinion may engagechain 46 along reach 51 to rotate rollers 36 in a direction to -advancethe work in accordance with travel arrow 40. p 2 f Ports 39 may beclosed by a port block 52 which as shown is divided into an uppersection 53 and a lower section 54 along a horizontal'line 55 passingthrough axis 37 at the operative height of thelrollers 36 in theillustrated furnace 10. Because of the shape of the ends 38 of theillustrated rollers 36, port block 52 is conically recessed at 56 on theinterface thereof while cylindrical opening 57 also formed by the twosections Ofblock .52

permits the reduced end of end 38 of the rollers 36 to pass from theinside of furnace 10 to the outside there of. A metal shell 58 havinginwardly extending flanges as shown in Figures 8 and 9 is completed withthe addition of a suitable castable refractory shape mounted therewithto provide the composite shape shown in such figures. The uppermostinwardly extending flange on facingSS is arched with the associatedrefractory to conform to the arched top of embrasure 22, or both the topof embrasure 22 and the top of port block 52 may be made straight. Theupper section of shell 58 is provided with a flange 59 which is boltedto plate 12 above the opening in that plate extending between channel'20 and the top of embrasure 22. Similarly, the metal facing 58 isprovided with side flanges 60 for bolting along the sides of embrasure22 to hold each of the sections 53 and 54 in place.

Although shown horizontally divided, :1 port block 52 maybe verticallyor otherwise parted for ease of installation'and removal as occasionrequires. Indeed, in the illustratedembodiment, upper section 53 ofport'block 52 ne ed not be removed nor is it necessary to remove thebrackets 45 extending across the outside of such upper sections 53 in'installing or removing roller 36. A wall block 61 with a port block 52constitutes a closure member for an embrasure 22; Such a wall block maybe of generally cubicalsection with an integral saddle crest 62 acrossthe top thereof inwardly of the outside of such block 61. The outside ofblock 61 is provided with a metal plate shell or facing 63 havinginwardly extending flanges 64, a horizontal outwardly extending flange65 and side flanges 66. Thus, facing 63 forms a cup on the inner sidethereof into which a refractory 67 may be cast to form block 61inclusive of saddle crest 62, the refractory 67- being suitable for thefurnace service to be incurred. Flanges 66 are also bolted or otherwiseremovably fastened in the same manner as the removable fastening of portblock 52 to the sides of the embrasure 22 in which such wall block 61 isplaced. Flange 65 fits on top of channel 20 and with a stiffening angle68, each wall block 61 may readily be moved inwardly and outwardly asoccasion requires. Some wall blocks 61 may be provided with centralopenings 69, as shown in Figure 7, to act as burner tunnels. Thus in theillustrated embodiment of furnace 10, alternate wall blocks 61 on eachside are provided with such tunnels 69, the burner tunnel blocks 61 ofwhich in each-bay are also staggered. Thus, since the axis 70 of eachblock 61 having a tunnel 69 therein is parallel to axis 37 and beneaththe same, furnace 10 may be so arranged in accordance with its desiredheating pattern, that one burner may fire beneath each roller 36 fromone side of the furnace toward the other. Combustion gases from suchunderhearth burning may rise between :rollers 36 Where not prevented bythe presence of work spanning such rollers toward flues 71 in the roofof furnace 10, through which flues 71 the combustion gases are exhaustedafter performing their heating function. If a change in the heatingcharacteristic of the furnace is required, the burner, which is notillustrated, may be withdrawn from alignment with a particular tunnel 69andthe tunnel may be closed by a cover plate 72, bolts being provided tofasten plates 72 to facing plates 63. Generally, plates 72 will beprovided with a refractory bung of suitable size, somewhat in the natureof bung 33, where a tunnel 69 is not in use, or a tunnel wall block 61may be withdrawn and a solid wall block such as those shown in FiguresSand 6 may be substituted therefor, as desired. Generally, a ,wall block61 and a port block 52 will fit closely enough for closure purposes,suitable distance being provided by the independent boltings, thereof tothe sides of an independent embrasure 22 to providev the expansion andcontraction space required in furnace service. I

In practice, a roller 36 may be installed, removed and/ or changed,readily, without cooling down a furnace, even if large, and withoutlikelihood of damage either to the roller or to the furnace structure,and without hazard to those engaged in any such activity. For such anoperation, a movable platform which may be in the form of a channel skid73 may be provided, or dolly wheels may be included along the bottom ofthe platform, if desired. As shown, platform skids 73 may be a channelsection having upstanding flanges 74 and a base 75. Sled ends 76 may bewelded to channel 73 and a perforation 77 provided through such ends forengagement thereof by a pole hook (not shown) or by chains 77a. Theheight of sides 74 is suflicient so that when carrying a roller as shownin dotted lines in Figure 11, the lowermost element 78 of such a rollerwill not touch either of the sled ends 76 or the bottom 75 of platform73. In removing a roller 36 in a furnace 10, for example, as shown inFigure 4, the wall blocks 61 beneath that particular roller 36 areremoved and the lower port block section 54 immediately above such wallblocks 61 is also removed. In such removal, as will be understood, if aburner is attached to one of the wall blocks 61 so removed, it is firstshut off and disconnected, since such burner connections are usuallymade in a readily disconnectible manner. Even on the drive side offurnace 10, the space between the upper and lower reaches of chain 46 issufficient to slide out a block 61, the block moving out across the topof channel 20 and onto level 15 outside of furnace 10, the level of thegrade along the sides of furnace 10. The outstanding flange of stiffener68 may be perforated to be engaged by hooks for such purpose after thebolts or nuts holding the blocks 61 to the side of embrasure 22 areloosened and removed. The port block section 54 may be loosened from thestructure of furnace 10, lowered and pulled out onto floor 15 at eachend of the roller 36 to be removed. Thereupon, a sling comprising a beam79, chains 79a and hooks 79b, suspended from a crane hook, for example,is maneuvered so that the hooks 79b engage the ends 38 of the roller 36outside of furnace 10. When the sling is just about in supportingrelation to a roller 36 engaged by it, bearings 42 can be disconnectedfrom brackets 45. Then, the crane hook can be lowered to lower suchroller 36 into a platform 73 in furnace beneath the roller as shown inFigure 4.

One relatively simple mode of positioning a platform 73 beneath a roller36 to be removed involves the use of two chains 77a as shown in Figure4. Such chains 77a are connected to the respective ends of platform 73through the holes 77. The leading chain 77a is provided with sufficientslack so that it may readily be snaked or projected through theappropriate embrasure 22 having the roller 36 to be engaged. The leadingchain 77a is pulled to pull platform 73 into the furnace 10. Then bothchains 77a. may be used to position platform 73 immediately beneath theroller 36 in that embrasure. When the roller 36 has been lowered intothe platform 73, the leading chain is again pulled, as shown in Figure4, to remove the lowered roller 36 by pulling it and the platform 73 outof furnace 10 onto floor into a position like that shown by dot-and-dashlines in Figure 4. The following chain 77a by the same operation ispulled so it extends through furnace 10 ready for a reversing operation.

Inasmuch as adjustment mechanism 41 may have tempered springs therein inone new kind of refractory roller 36, such a roller 36 would be removedby pulling skid 73 in the direction of arrow 80 whereby mechanism 41would not pass through furnace 10 which, as described above, may stillbe hot since no cooldown is required under a practice of this invention,although preferably the other burners in furnace 10 which are at leastadjacent to the roller 36 being removed, will have been shut off orturned down before opening the side Walls of furnace 10 immediatelybeneath the roller 36 to be so removed.

Either in setting up a furnace 10 or in replacing a roller 36 removed asdescribed above with the same or with another roller 36, the steps justrecited are reversed. That is, a roller 36 is placed on a platform 73 onthe right-hand side of a furnace 10 if the roller 36, for example, hasan adjustment mechanism 41 therein. wise, the insertion of a roller 36into a furnace 10 may take place from either side.

With a roller 36 on skid 73 outside of furnace 10, the platform is thenpulled back into furnace 10 by the trailing chain 77a, on the right-handside of Figure 4, which moved into the furnace 10 at the time thepreceding roller 36 was removed from that embrasure. When the ends 38 ofsuch a newly inserted roller 36 project beyond the respective sides offurnace 10, both ends 38 may be engaged by the hooks 79b. Thereupon,'thesling 79 is raised also raising the bearings 42 in the illustratedembodiment until such bearings 42 can be coupled to their respectivebrackets 45. At that point, skid 73 and chains 77a are removed fromfurnace 10, the sling is loosened and carried off and the port blocksections 54 and the wall blocks 61 are replaced. If one of those wallsections has a burner tunnel 69 therein, the burner can be reconnectedto the outer end of that tunnel and the furnace is ready to start orresume operation as the case may be.

In the case of relatively small furnaces, it may be possible to conductsuch a roller installation replacement or change by removal ofwall'member sections on one side onlyof the furnace, since the leadingend of the roller may be-tilted upwardly, for example, by a bar insertedthrough the port on the side of the furnace away from the wall openingto guide such leading end of the roller through its port and portopening. Once in transverse position, such a smaller furnace roller canbe. reconnected and the open embrasure reclosed so that furnaceoperations can commence or recommence.

Various modifications may be made in the aspects of this inventionwithout departing from the spirit thereof or the scope of the appendedclaims.

I claim:

1. In a roller hearth furnace, in combination, a side wall having anembrasure for a roller, said embrasure extending from the operativeheight at which said roller operates in said furnace downwardlysubstantially at least to the height of flooring alongside said wall,means for rotata'bly supporting said roller at said operative height insaid furnace, and at least one wall member closing said embrasure whichis removable below said operative height, whereby when said removablewall member is removed and said roller is disengaged from its support,it may be lowered and removed from said furnace at the level of thebottom of said embrasure.

2. In a roller hearth furnace, in combination, side walls, opposedembrasures in said side walls for a roller, said embrasures extendingfrom the operative height of said roller in said furnace substantiallyto an outside support alongside said side walls and below said operativeheight, a bracket connected to said furnace adjacent each of saidembrasures, a bearing supported by said bracket to support an end ofsaid roller in operative position, a removable wall block closing thelower part of each of said embrasures, and a port block closing each ofsaid embrasures at said operative height, said port blocks having anopening for the ends of said roller to pass from the inside of saidfurnace to said bearings.

3. In a roller hearth furnace, in combination, side walls, opposedembrasures in said side walls for a roller, said embrasures extendingfrom the operative height of said roller in said furnace substantiallyto a generally fiat support alongside said side walls and below saidoperative height, a bracket connected to said furnace adjacent each ofsaid embrasures, said bracket having a portion above the center line ofsaid roller when said roller is at said operative height, a bearingsuspended from said bracket to support an end of said roller inOtherflooring alongside-said walls, a bracket connected to said furnaceand extending across the outside of each of said embrasures, saidbracket having a portion adjacent the center line of said roller whensaid roller is at operative height in said furnace, a bearing mounted onsaid bracket to support an end of said roller in operative position atsaid operative height, a removable wall block closing the lower part ofeach of said embrasures, said wall block consisting at least in part ofinsulating ma- ;terial and having a shape fittinglinto such lower partof each of said embrasures to provide a closure section of said sidewalls, and a port block closing each of said embrasures above said wallblocks, said port blocks consisting at-least in part of insulatingmaterial and having a shape fitting into each of said embrasures toprovide a removable port closure section of said side walls, each ofsaid port blocks being divided and having an opening along its line ofdivision for the passage of an end of said roller from the inside ofsaid furnace to the bearings adjacent said port blocks respectively.

5. In an operation of a roller hearth furnace having walls and a rollerat operative height extending between said walls, thesteps comprising,in combination, support- "ing said roller at said operative height fromabove the center line of said'roller, removing wall sections adjacentthe ends of said roller to provide openings in said furnace wallsextending downwardly from said operative height, extending a platformfor said roller into said furnace through one of said openings to aposition beneath said roller, releasing said roller from its supports,lowering said roller onto said platform, and moving said platform out ofsaid furnace through one of said openings to remove said roller belowsaid operative height.

6. In an operation of a roller hearth furnace having parallel verticalside walls extending upwardly from grade, embrasures and removableclosures therefor extending from said grade upwardly at least tooperative height of the rollers in said furnace, said rollers havingtheir respective ends projecting through openings in said closuresduring operation at said operative height, said rollers further beingsupported at said operative height from above the center line of saidrollers, the steps comprising, in combination, removing said closuresadjacent the ends of a roller to be removed to uncover said embrasures,moving a platform at grade into said furnace beneath said roller,releasing said roller from its supports, lowering said roller by meansoutside said furnace onto said platform, moving said platform and rollerout of said furnace through one of said embrasures, and trailing a chainbehind said platform and into said furnace during said last-mentionedmoving whereby reversing the References Cited in the file of this patentUNITED STATES PATENTS Lee Oct. 26, 1926 Kathner May 15, 1928 KathnerAug. 20, 1929

